The patent war between Microsoft and TomTom may be resolved in court, but it hasn't ended. At least that's what the lawyers at the Software Freedom Law Center think, and Jim Zemlin of the Linux Foundation is further considering the implications.

The navigation software provider TomTom had recently filed a countersuit against Microsoft's allegation of patent violations, which led to an agreement whereby TomTom paid an undisclosed amount to Microsoft. TomTom also agreed to remove two functions out of its product related to Microsoft's FAT-LFN patents over the next two years. The outcome is not only an interesting development for Linux providers when considering Microsoft's regular patent arsenal threats, but because the patents also affect Linux technologies. TomTom had just that in mind when it appealed to the Open Invention Network (OIN) for help with its countersuit. Together with the Linux Foundation and lawyers of the Software Freedom Law Center (SFLC), the OIN intends to take action to prevent further Microsoft lawsuits against open source users and developers.

In a message from the SFLC, their lawyers represent the view that the settlement might temporarily have spared TomTom a protracted court process, but that it "ends one phase of the community's response to Microsoft patent aggression and begins another." As they say, "The FAT filesystem patents on which Microsoft sued are now and have always been invalid patents in our professional opinion." A comment on the agreement from the Red Hat legal team sees things quite similarly.

Jim Zemlin, Executive Director of the Linux Foundation, wants to resolve the filesystem issue on a technical basis. In a recent blog, Zemlin approached it as nutritionist: "Maybe it’s time developers go on a diet from Microsoft and get the FAT out of their products." He takes his tip from an unexpected source: "As acknowledged by Microsoft in the press release, this file system is easily replaced with multiple technology alternatives." He goes on, "The Linux Foundation is here to assist interested parties in the technical coordination of removing the FAT filesystem from products that make use of it today."

Back at the start of the patent battle, Zemlin had tried in a blog to assuage any concerns and perhaps give Microsoft the benefit of the doubt when it came to open source software violations, until proven otherwise. Obviously the "proven otherwise" has occurred: "Microsoft does not appear to be a leopard capable of changing its spots."

The Open Invention Network (OIN) has publicized on Post-Issue.org the three patents involving the FAT filesystem that were used by Microsoft in a lawsuit against TomTom, so that the OIN might gather evidence from the community about prior art.